Human Salty And Bitter Taste Mechanisms
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Transcript of Human Salty And Bitter Taste Mechanisms
Diana Frank2008 Summer Research Fellowship
Principal Investigator: Dr. Marion FrankStudy Coordinator: Dr. Larry Savoy
Introduction Taste Cells
Taste PoreMicrovilliGustatory afferent nerve
Taste MechanismsSalty: Na+ passage through Na+ channelsSour: H+ passage through Na+ channels or
blockage of K+ channelsSweet: G protein-coupled processesBitter: G protein-coupled processes or
blockage of K+ channels
Taste Bud Regions CN VII-Facial Nerve
Fungiform: innervated by the Chorda Tympani (CT) branch
Palate: innervated by the Greater Superficial Petrosal (GSP) branch
CN IX- Glossopharyngeal (GL) NerveFoliate: innervated by the lingual branchCircumvallate Papillae: innervated by the lingual
branch
Diagram of tongue and palate showing regions stimulated in the Spatial Taste Test. (Figure modified from Bartoshuk [1989]).
Circumvallate
PalateFoliate
Fungiform
Taste Study
ChlorhexidineThe active ingredient in the prescription
mouthwash, Peridex*, to treat GingivitusAffects salty and bitter taste qualities and
intensitiesHas a bitter taste
Why is Chlorhexidine’s effect on taste so interesting?
Regional Specificity of Chlorhexidine Effects on Taste
PerceptionGrover and Frank, 2008
Chlorhexidine reduced the intensity of NaCl at fungiform and palatal area stimulation sites (CN VII)
Control intensity ratings were significantly higher at foliate and circumvallate sites (CN IX)
The increased sensitivity of 9th nerve sites could have affected the results
Hypothesis
The decrement in NaCl intensity ratings with CHX rinses would remain larger for CN VII than CN IX regions
The decrement in quinine intensity ratings with CHX rinses would remain equal for CN VII than CN IX regions
Lowering the concentrations for CN IX areas would not produce results different from the Grover et al study
Materials and Methods Subjects: 6 subjects (anticipated), aged 18-
28 Exclusion Criteria: non-smokers, no history
of taste and smell disorders, and in general good health
Consists of a single, 1 hour session Subjects are compensated $8
Materials and Methods 2 training trials to familiarize subjects with
taste stimuli and experience rating intensities using the 0-9 point, fixed interval scaleTraining solutions:
○ 0.1M NaCl (Salty), 0.1M Sucrose (Sweet), 3mM Citric Acid (Sour), Water (Tasteless), and 0.1mM Quinine (Bitter)
1st trial: solution identity given2nd trial: subject identifies and rates solution
intensity
Fixed Interval Scale
Taste Qualities
Data Collection
Materials and Methods
Subject rinses with a rinse and then given a 5 minute break
Subject is given a diagram of the areas of the mouth to be tested (show diagram again)
Materials and Methods Two testing sessions
Test solutions:
1st session: 3 - 5mL water rinses2nd session: 3 - 5mL 1.34 mM CHX rinses
CN VII CN IX
NaCl 1 M 0.32 M
Quinine 1 mM 0.32 mM
Sucrose 1 M 0.32 M
Materials and Methods Each taste stimulus was
sequentially applied to the same areas: fungiform, foliate, circumvallate, and palate
Before each solution was applied, subject was given directions on how to present mouth (by experimenter demonstration)
Preliminary Results
NaCl Quinine Sucrose
Preliminary Results
Related Article Green, B.G. and Schullery, M.T. (2003)
Stimulation of Bitterness by Capsaicin and Menthol: Differences Between Lingual Areas Innervated by the Clossopharyngeal and Chorda Tympani Nerves. Chem. Senses 28: 45-55.
Introduction
Capsaicin is traditionally used to desensitize a class of trigeminal nervesEvokes sensations of heat and acidity-
producing a burning sensation
Menthol is used as an artificial cooling agent
There is minor evidence that capsaicin and methnol may have gustatory properties
Hypothesis
Capsaisin and Menthol would both stimulate taste via different gustatory nerves
Methods and Materials
Results
Results
Conclusions
Capsaicin and menthol produced moderate bitterness in the circumvallate region and weak bitterness in the folliate and fungiform regions
Sensory irritation from Capsaicin was rated significantly higher at the fungiform region
Menthol coolness was rated higher in the circumvallate region
AcknowledgementsMarion Frank
Thomas Hettinger
Larry Savoy
Jonathan Ryder
Kelly O’Neil
Lesley Mancini
Tom Kiely
Kathy Salomone
Lisa Burgio